Path Planning of an Inchworm-like Robot in 3D Environment Based on Improved Ant Colony Algorithm

To solve the global path planning of a 7-degree-of-freedom inchworm robot in a 3D hybrid environment of "pipe + wall", a planning method based on the A*-inspired ant colony algorithm is proposed. First of all, the coordinates of the reachable points are obtained by modelling the environment, and the set of reachable points is determined by combining with the workspace of the inchworm robot. Then, a heuristic function based on the A* algorithm is designed to improve the convergence speed of the algorithm; at the same time, a bending suppression operator is added to the heuristic function to reduce the problems of a large number of bending times and large cumulative bending angle caused by the A* algorithm. Finally, the maximum minimum ant system (MMAS) is introduced to solve the premature phenomenon that the traditional ACO algorithm may cause. The simulation results show that the method suits the three-dimensional environments of pure pipe, pure wall and "pipe+wall".